1.3 Resonant Sensing Applications Tricks and Tips

And this begins our Tricks and Tips section, starting with achieving the lowest power with LDC and FDC devices. The LDC0851 is one of our inductive switch devices. It's primarily used for open and close applications like tamper detection, as well as event counting applications like incremental encoders or knobs. It's typical power consumption depends on the sensor, but it's anywhere between two to three milliamps.
Now, in order to achieve low power in the microamp range, we recommend to duty cycle the enable pin, which can be done with a low power micro like an MSP430 or one of our nano timer devices, such as the TBL devices. Now, the average power consumption depends on the wake-up time of the LDC and the sensory characteristics.
So what we've done is we've developed a calculator tool to make it easier to design for a specific sample rate and power consumption. This tool allows you to enter the battery capacity, desired sample rate, as well as the enable pulse duration from the MCU, and then calculates the average current consumption, as well as the expected battery lifetime. Now, you can find this tool on the web by clicking the link below or by visiting ti.com/ldc and navigating to the Tools and Software section.
Similarly, the LDC161x and the FDC221x devices can be duty cycled with an MCU, but it has to be done over the I2C bus. Because it's a bit more involved, we've written an app note in addition to the spreadsheet calculator tool, but both of these can be found by clicking on the links below or by visiting ti.com/ldc.
And just recently, we've released a new device that incorporates the duty cycling feature internally, so no additional work is needed by the MCU to achieve low power. The LDC2114 is a micropower device that's well-suited for battery power applications, such as metal touch buttons for wearables and personal electronics. The spreadsheet calculator tool allows you to compute the expected power consumption based on the target sample rate and also includes a number of other useful calculations, including the recommended register settings.
So click on the link below to access the spreadsheet tool or visit ti.com/ldc for more info. And I should note that the calculator tool discussed here and for the other devices is the same spreadsheet. And it also includes a lot of other useful calculations. So overall, it's a good tool to have in your tool belt if you're doing LDC or FDC applications.
Now, let's cover the second section of our tricks and tips, common sticking points when prototyping with LCD and FDC devices. One of the more common issues is when the user uploads a new firmware or the wrong firmware and it breaks the EVM. Fortunately, you don't need to buy a new VM, because we've included an MSP430 on the EVM, which has a BSL mode.
Here I'll give the example of how to enter BSL mode and reload the correct firmware using the FDC1004 EVM. First is to identify the PUR and VUSB pins on the EVM. This can be done by looking at the schematic and layout, which is included on the product page for the EVM.
For the FDC1004, it's R40 and C6. Now, with the device powered off, you should short these two pins. I typically use a pair of metal tweezers or a paper clip to do this. Then, with your free hand, connect the power to the board, and the EVM should now be in BSL mode.
To load the correct firmware, you can use the Python firmware upgrader included with the MSP430 development pack. Instructions for downloading and installing are shown here. Now, when you load the program it should say ready. If that's not the case, then the device is not in BSL mode, and you have to redo the first step.
Once in BSL mode, you can load the correct firmware, which is automatically downloaded by the sensing solutions GUI. I show the location and instructions here. Once you load the firmware and it says Programming OK, you should be all set. If you open the Device Manager, it should now show up in the COM port as EVM, and you can use your board once again.
This solution, along with many others, can be found on our FAQ page shown here. If you find yourself stuck, the solution to your problem may already be documented online. Now, if you don't see your problem or the solution isn't listed here, you can also visit the E2E forums, where we have a team of engineers who will assist you with your issue and provide a response within 24 hours.
This concludes today's presentation. Once again, my name is Luke Lapointe, and I want to thank you for your time.